Share this with others: Alcohol, which is consumed in beverages such as liquor, wine and beer, is a chemical called ethanol. Ethanol may cause headaches by several means. First, it is a direct vasodilator; in some individuals vasodilation may cause a headache.
In medicine, a contraindication is a condition or factor that serves as a reason to withhold a certain medical treatment due to the harm that it would cause the patient. Contraindication is the opposite of indication, which is a reason to use a certain treatment. Some contraindications are absolute, meaning that there are no reasonable circumstances for undertaking a course of action.
Each test has its own indications and contraindications. An indication is a valid medical reason to perform the test. A contraindication is a valid medical reason to reject the test. For example, a basic cholesterol test may be indicated (medically appropriate) for a middle-aged person.